Air cushion



FIG. 1 is a front view of an air cushion, showing my new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a bottom plan view thereof;

FIG. 4 is a rear plan view thereof;

FIG. 5 is a left plan view thereof;

FIG. 6 is a right plan view thereof; and,

FIG. 7 is a perspective view thereof. 

CLAIM The ornamental design for an air cushion, as shown and described. 